Itself, or any object contained in the figure.

DATA can be anything an application wishes to store for later

retrieval.

DATA = GUIDATA(H) returns previously stored data, or an empty

matrix if nothing was previously stored.

GUIDATA provides application authors with a convenient interface

to a figure's application data. You can access the data from a

callback subfunction using the component's handle, without needing

to find the figure's handle. You can also avoid having to create

and maintain a hardcoded property name for the application data

throughout your source code. GUIDATA is particularly useful in

conjunction with GUIHANDLES, which returns a structure containing

handles of all the components in a GUI listed by tag.

Example:

Suppose an application creates a figure with handle F, containing

a slider and an editable text uicontrol whose tags are

'valueSlider' and 'valueEdit' respectively. The following

excerpts from the application's MATLAB code illustrate the use of

GUIDATA to access a structure containing handles returned by

GUIHANDLES, plus additional application-specific data added during

initialization and callbacks:

... excerpt from the GUI setup code ...

f = openfig('mygui.fig');

data = guihandles(f); % initialize it to contain handles

data.errorString = 'Total number of mistakes: ';

data.numberOfErrors = 0;

guidata(f, data); % store the structure

... excerpt from the slider's callback ...

data = guidata(gcbo); % get the struct, use the handles:

set(data.valueEdit, 'String',...

num2str(get(data.valueSlider, 'Value')));

... excerpt from the edit's callback ...

data = guidata(gcbo); % need handles, may need error info

val = str2double(get(data.valueEdit,'String'));

if isnumeric(val) & length(val)==1 & ...

val >= get(data.valueSlider, 'Min') & ...

val <= get(data.valueSlider, 'Max')

set(data.valueSlider, 'Value', val);

else

% increment the error count, and display it

data.numberOfErrors = data.numberOfErrors + 1;

set(handles.valueEdit, 'String',...

[ data.errorString, num2str(data.numberOfErrors) ]);

guidata(gcbo, data); % store the changes...

end

Note that GUIDE generates callback functions to which a structure

of handles is passed automatically as an input argument. This

eliminates the need to call "data = guidata(gcbo);" in callbacks

written using GUIDE, unlike the example above.

See also guihandles, guide, openfig, getappdata, setappdata.

Reference page in Help browser

doc guidata

<guihandles> - Return a structure of handles.

GUIHANDLES Return a structure of handles.

HANDLES = GUIHANDLES(H) returns a structure containing handles of

objects in a figure, using their tags as fieldnames. Objects

are excluded if their tags are empty, or are not legal variable

names. If several objects have the same tag, that field in the

structure contains a vector of handles. Objects with hidden

handles are included in the structure.

H is a handle that identifies the figure - it can be the figure